This report describes the second year of a longitudinal study designed to prevent the development of risk factors for cardiovascular disease. Subjects are a cohort of 1,482 school students, male and female, who are now in the 5th grade. The prevention method is a school-based health education program implemented by classroom teachers. A 10-module curriculum includes material on decision making, nutrition, physical exercise, and smoking prevention. An experimental design has been established with three study districts, where children receive the complete health education curriculum at school, and three control districts. Evaluation data are reported for changes observed through the beginning of Year 2 of the study. Significant increases in health knowledge were noted for children in study schools (compared with controls) during Year 1, and these changes were maintained into Year 2. Biomedical measures indicated significant (although small) improvement in cardiovascular fitness that was attributable to the health education program. Serum thiocyanate values were significantly higher for the control group in Year 2, indicating an early effect of the educational program for prevention of cigarette smoking. Self-report data indicated a significant decrease in butterfat consumption for children in the study group. Overall program effects were moderated by sex differences, with different patterns of change noted for males and females. Additional data on dietary patterns, health attitudes, and physical exercise are still being analyzed. It is concluded that the educational program has a significant early effect for preventing development of cardiovascular risk factors.